1. Field of the Invention
The present invention concerns a unique unfired refractory article or brick capable of withstanding temperatures of up to 3,200.degree. F. and above which is characterized by its resistance to thermal shock and general chemical inertness in a molten metal environment.
Broadly stated, the present invention relates to an improved unfired refractory brick which includes a mixture of fine silica sand particles having a particle size ranging from about 0.06 mm to about 1.0 mm and coarse silica sand particles having a particle size of up to about 3.0 mm which are bonded together by a clay binder.
2. Description of the Prior Art
It is well known to process or transport molten metals, particularly iron base metals, in vessels or receptacles which are lined with refractory materials. For example, in the handling or processing of pig iron it is common practice to line the receiving vessel or ladle with calcined fire-clay bricks which have an alumina content as high as 35 weight percent.
In general, the receiving vessel or ladle is usually provided with a refractory lining which consists of a plurality of individual bricks held in place by a suitable mortar. While this type of refractory brick performs well in most instances, it nevertheless suffers from certain inherent deficiencies. For example, often times the mortar is attacked by slag and/or the molten metal being processed. This causes the mortar to erode and results in the formation of so-called "cat-heads", i.e., the rounding of the surface of the brick in contact with the molten metal, on the individual bricks which make up the vessel lining. Ultimately, the molten metal permeates the spacing between juxtapositioned bricks and causes liner failure to occur.
In addition, most refractory brick used for the foregoing purpose tend to shrink when contacted by molten iron based metals. This causes the mortar to separate from the brick and permits molten metal to fill the so-formed void. In due course, this causes the lining to fail.
Accordingly, it is the principal object of the present invention to provide a means for overcoming the before discussed problems by providing a unique refractory brick.
Other objects of the invention will be apparent to those skilled in the art from a reading of the specification and claims.